Gödel, Escher, Bach: An Eternal Golden Braid

more from “Gödel, Escher, Bach: An Eternal Golden Braid“:

information-revealers — devices like a record or CD player which can pull information out of an information-bearer

information-bearer — a device that holds information…

Those words aren’t very exciting until you start thinking about stuff like this:

“Take the case of the genetic information commonly said to reside in the double helix of deoxyribonucleic acid (DNA). A molecule of DNS — a genotype — is converted into a physical organism — a phenotype — by a very complex process, involving the manufacture of proteins, the replication of the DNA, the replication of cells, the gradual differentiation of cell types, and so on. Incidentally, this unrolling of phenotype from genotype — epigenesis — is the most tangled of tangled recursions… Epigenesis is guided by a set of enormously complex cycles of chemical reactions and feedback loops. By the time the full organism has been constructed, there is not even the remotest simliarity between its physical characteristecs and its genotype. … And yet, it is standard practice to attribute the physical structure of the organism to the structure of its DNA, and to that alone. The first evidence for this point of view came from experiments conducted by Oswald Avery in 1946, and overwhelming corroborative evidence has since been amassed. Avery’s experiments showed that, of all the biological molecules, only DNA transmits hereditary properties. One can modify other molecules in an organism, such as proteins, but such modifications will not be transmitted to later generations. However, when DNA is modified, all successive generations inherit the modified DNA. Such experiments show that the only way of changing the instructions for building a new organism is to change the DNA — and this, in turn, implies that those instructions must be coded somehow in the structure of DNA.” [pg 158]

Still with Douglas? Continuing on with the next paragraph: “Therefor one seems forced into accepting the idea that the DNA’s structure contains the information of the phenotype’s structure, which is to say, the two are isomorphic. However, the isomorphism is an exotic one, by which I mean that it is highly nontrivial to divide the phenotype and the genotype into “parts” which can be mapped onto each other. Prosaic isomorphisms by contrast, would be ones into which the parts of one structure are easily mappable onto the parts of the other. An example is the isomorphism between a record and a pice of music, where one knows that to any sound in the piece there exists an exact “image” in the patterns etched into the grooves, and one could pinpoint it arbitrarily accurately, if the need arose… The isomorphism between DNA structure and phenotype structure is anything but prosaic, and the mechanism which carries it out physically is awesomely complicated. For instance, if you wanted to find some piece of your DNA which accounts for the shape of your nose or the shape of your fingerprint, you would have a very hard time. It would be a little like trying to pin down the note in a piece of music which is the carrier of the emotional meaning of the piece. Of course there is no such note, because the emotional meaning is carried on a very high level, by large “chunks” of the piece, not by single notes. Incidentally, such “chunks” are not necessarily sets of contiguous notes; there may be disconnected sections which, taken together, carry some emotional meaning.” [pg 160]

Page 168 has a fascinating collage of various scripts including Mongolian and Buginese. It boggles my mind that the words I’m writing right now using the English alphabet mean absolutely nothing to people in other parts of the world.

All for tonight…

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